C# - Line Bricklet

This is the description of the C# API bindings for the Line Bricklet. General information and technical specifications for the Line Bricklet are summarized in its hardware description.

An installation guide for the C# API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Simple

Download (ExampleSimple.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Line Bricklet

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLine l = new BrickletLine(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Get current reflectivity
        int reflectivity = l.GetReflectivity();
        Console.WriteLine("Reflectivity: " + reflectivity);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Callback

Download (ExampleCallback.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Line Bricklet

    // Callback function for reflectivity callback
    static void ReflectivityCB(BrickletLine sender, int reflectivity)
    {
        Console.WriteLine("Reflectivity: " + reflectivity);
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLine l = new BrickletLine(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Register reflectivity callback to function ReflectivityCB
        l.ReflectivityCallback += ReflectivityCB;

        // Set period for reflectivity callback to 1s (1000ms)
        // Note: The reflectivity callback is only called every second
        //       if the reflectivity has changed since the last call!
        l.SetReflectivityCallbackPeriod(1000);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

Threshold

Download (ExampleThreshold.cs)

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using System;
using Tinkerforge;

class Example
{
    private static string HOST = "localhost";
    private static int PORT = 4223;
    private static string UID = "XYZ"; // Change XYZ to the UID of your Line Bricklet

    // Callback function for reflectivity reached callback
    static void ReflectivityReachedCB(BrickletLine sender, int reflectivity)
    {
        Console.WriteLine("Reflectivity: " + reflectivity);
    }

    static void Main()
    {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletLine l = new BrickletLine(UID, ipcon); // Create device object

        ipcon.Connect(HOST, PORT); // Connect to brickd
        // Don't use device before ipcon is connected

        // Get threshold callbacks with a debounce time of 1 second (1000ms)
        l.SetDebouncePeriod(1000);

        // Register reflectivity reached callback to function ReflectivityReachedCB
        l.ReflectivityReachedCallback += ReflectivityReachedCB;

        // Configure threshold for reflectivity "greater than 2000"
        l.SetReflectivityCallbackThreshold('>', 2000, 0);

        Console.WriteLine("Press enter to exit");
        Console.ReadLine();
        ipcon.Disconnect();
    }
}

API

Generally, every method of the C# bindings that returns a value can throw a Tinkerforge.TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody plugs the device out). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Since C# does not support multiple return values directly, we use the out keyword to return multiple values from a method.

The namespace for all Brick/Bricklet bindings and the IPConnection is Tinkerforge.*.

All methods listed below are thread-safe.

Basic Functions

public class BrickletLine(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletLine line = new BrickletLine("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected (see examples above).

public int GetReflectivity()

Returns the currently measured reflectivity. The reflectivity is a value between 0 (not reflective) and 4095 (very reflective).

Usually black has a low reflectivity while white has a high reflectivity.

If you want to get the reflectivity periodically, it is recommended to use the ReflectivityCallback callback and set the period with SetReflectivityCallbackPeriod().

Advanced Functions

public byte[] GetAPIVersion()

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

public bool GetResponseExpected(byte functionId)

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by SetResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See SetResponseExpected() for the list of function ID constants available for this function.

public void SetResponseExpected(byte functionId, bool responseExpected)

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • BrickletLine.FUNCTION_SET_REFLECTIVITY_CALLBACK_PERIOD = 2
  • BrickletLine.FUNCTION_SET_REFLECTIVITY_CALLBACK_THRESHOLD = 4
  • BrickletLine.FUNCTION_SET_DEBOUNCE_PERIOD = 6
public void SetResponseExpectedAll(bool responseExpected)

Changes the response expected flag for all setter and callback configuration functions of this device at once.

public void GetIdentity(out string uid, out string connectedUid, out char position, out byte[] hardwareVersion, out byte[] firmwareVersion, out int deviceIdentifier)

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

Callback Configuration Functions

public void SetReflectivityCallbackPeriod(long period)

Sets the period in ms with which the ReflectivityCallback callback is triggered periodically. A value of 0 turns the callback off.

The ReflectivityCallback callback is only triggered if the reflectivity has changed since the last triggering.

The default value is 0.

public long GetReflectivityCallbackPeriod()

Returns the period as set by SetReflectivityCallbackPeriod().

public void SetReflectivityCallbackThreshold(char option, int min, int max)

Sets the thresholds for the ReflectivityReachedCallback callback.

The following options are possible:

Option Description
'x' Callback is turned off
'o' Callback is triggered when the reflectivity is outside the min and max values
'i' Callback is triggered when the reflectivity is inside the min and max values
'<' Callback is triggered when the reflectivity is smaller than the min value (max is ignored)
'>' Callback is triggered when the reflectivity is greater than the min value (max is ignored)

The default value is ('x', 0, 0).

The following constants are available for this function:

  • BrickletLine.THRESHOLD_OPTION_OFF = 'x'
  • BrickletLine.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletLine.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletLine.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletLine.THRESHOLD_OPTION_GREATER = '>'
public void GetReflectivityCallbackThreshold(out char option, out int min, out int max)

Returns the threshold as set by SetReflectivityCallbackThreshold().

The following constants are available for this function:

  • BrickletLine.THRESHOLD_OPTION_OFF = 'x'
  • BrickletLine.THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletLine.THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletLine.THRESHOLD_OPTION_SMALLER = '<'
  • BrickletLine.THRESHOLD_OPTION_GREATER = '>'
public void SetDebouncePeriod(long debounce)

Sets the period in ms with which the threshold callback

is triggered, if the threshold

keeps being reached.

The default value is 100.

public long GetDebouncePeriod()

Returns the debounce period as set by SetDebouncePeriod().

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done by appending your callback handler to the corresponding event:

void MyCallback(BrickletLine sender, int value)
{
    System.Console.WriteLine("Value: " + value);
}

line.ExampleCallback += MyCallback;

The available events are described below.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

public event ReflectivityCallback(BrickletLine sender, int reflectivity)

This callback is triggered periodically with the period that is set by SetReflectivityCallbackPeriod(). The parameter is the reflectivity of the sensor.

The ReflectivityCallback callback is only triggered if the reflectivity has changed since the last triggering.

public event ReflectivityReachedCallback(BrickletLine sender, int reflectivity)

This callback is triggered when the threshold as set by SetReflectivityCallbackThreshold() is reached. The parameter is the reflectivity of the sensor.

If the threshold keeps being reached, the callback is triggered periodically with the period as set by SetDebouncePeriod().

Constants

public int DEVICE_IDENTIFIER

This constant is used to identify a Line Bricklet.

The GetIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

public string DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Line Bricklet.